APPLICATION OF A SEMI-ANALYTIC SEAWIFS ALGORITHM FOR CHLOROPHYLL-A AND GELBSTOFF

Tests of a semi-analytic (SA) SeaWiFS algorithm for chlorophyll and gelbstoff were made in the clean seawaters off the Tongue of The Ocean (TOTO), and the gelbstoff-rich waters of the west Florida shelf (WFS). Record winter rainfall over Florida and the southeastern U.S. in 1998 resulted in very high river runoff and colored dissolved organic matter (gelbstoff) in the coastal waters. For the offshore stations in the TOTO, the SA algorithm for chlorophyll delivered concentrations consistent with in situ data and the default NASA algorithm. For the near-shore TOTO and WFS regions, however, the default NASA algorithm delivered values high by factors from 2X to 4X, due to the high gelbstoff present. The SA algorithm provided chlorophyll and gelbstoff values for coastal and offshore regions with RMS errors less than 20%. Using the SA algorithm, it was determined that a wide halo of gelbstoff surrounded the entire Florida peninsula during May and June.